For more than four decades, scientists have grappled with an elusive chemical found in treated drinking water across the United States. This ongoing mystery has finally begun to unravel, as recent research sheds light on the nature of this compound. A study published in the journal *Science* identifies the culprit as chloronitramide anion, a decomposition byproduct of chloramine—a compound that numerous water treatment facilities utilize to make drinking water safe. An estimated 113 million Americans rely on tap water that potentially exposes them to this newly identified anion.
While the specific health effects of the chloronitramide anion remain ambiguous, the study’s authors note that its properties resemble those of other toxic molecules subject to government regulations. Such parallels raise concerns, especially since there is historical precedence for disinfection byproducts created from drinking water purification processes being potential carcinogens. Early 20th-century public health efforts successfully eliminated cholera and typhoid fever through the introduction of chlorine, yet this solution introduced new health issues, including increased risks of certain cancers for long-term chlorinated water consumers.
Epidemiological evidence has indicated that long-term ingestion of chlorinated water correlates with an elevated risk of colon and bladder cancers, as well as associations with miscarriages and low birth weight infant cases among pregnant individuals. Though chlorine remains safe at low concentrations, it can produce toxic byproducts when interacting with natural elements in the water.
As a result, the Environmental Protection Agency (EPA) places limits on the amount of byproducts allowed in drinking water, ensuring safety for consumers. However, many water providers have shifted to using chloramine—a compound formed by combining chlorine and ammonia—due to its stability and longer-lasting effects. Unfortunately, scientists have recently discovered that chloramine also leads to the formation of byproducts, one of which remained unidentified and puzzled researchers Dr. Julian Fairey and Dr. David Wahman for years.
Beginning their quest after graduate studies, the duo sought to uncover the chemistry behind this unknown compound. Despite their initial enthusiasm, it took them a painstaking 15 years to solve this mystery. Their breakthrough occurred with the help of Dr. Juliana Laszakovits, a mass spectrometry expert, who employed advanced analysis methods to determine the compound’s molecular weight and characteristics.
Laszakovits encountered challenges due to the high salinity of the water samples, necessitating the innovative use of ion chromatography combined with mass spectrometry—a method not commonly employed in environmental studies. The results confirmed the compound’s structure, leading Fairey to replicate the compound to establish its properties convincingly. Meanwhile, Wahman’s inquiries into whether chloronitramide anions were present in US drinking water systems using chloramines revealed their absence in Swiss systems lacking the compound.
Despite these discoveries, the potential toxicity of chloronitramide anion remains uncharted. While its presence is anticipated in chlorinated drinking waters, further studies are crucial to ascertain any public health implications. Water expert Dr. David Sedlak emphasized the need for in-depth toxicological investigations into recently discovered chloramine byproducts, hinting at a possible reconsideration of the switch from chlorine to chloramines for water disinfection.
Local water systems often lack the funding necessary to explore the health impacts of such compounds, placing the onus on federal agencies to address these pressing questions. According to Sedlak, the financial resources traditionally allocated to monitoring new pharmaceuticals should also extend to ensuring the safety of drinking water.
Experts in chemistry, including Dr. Oliver Jones from RMIT University in Melbourne, have remarked on the elegant techniques employed in the study while suggesting that the mere presence of a compound should not be equated with harm. He echoed a common sentiment among researchers that every substance can be toxic at certain doses, but the levels encountered in everyday exposure—such as through tap water—are unlikely to pose significant risks. In light of ongoing inquiries, the study authors recommend concerned individuals consider using carbon-based filters, like Brita filters, to mitigate any potential exposure while further research continues.